Disk formatter and methods for use therewith

ABSTRACT

A disk formatter includes an address module for creating disk block address data corresponding to a disk sector of a disk drive. A sector write module initiates a physical mode write operation to the disk sector that incorporates the corresponding disk block address data.

CROSS REFERENCE TO RELATED PATENTS

Not applicable

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to disk formatters, disk drives andrelated methods.

2. Description of Related Art

As is known, many varieties of disk drives, such as magnetic disk drivesare used to provide data storage for a host device, either directly, orthrough a network such as a storage area network (SAN) or networkattached storage (NAS). Typical host devices include stand alonecomputer systems such as a desktop or laptop computer, enterprisestorage devices such as servers, storage arrays such as a redundantarray of independent disks (RAID) arrays, storage routers, storageswitches and storage directors, and other consumer devices such as videogame systems and digital video recorders. These devices provide highstorage capacity in a cost effective manner.

As a magnetic hard drive is manufactured it is formatted at the factory.The formatting process typically includes at least one stage where datais read to the drive in a physical mode corresponding to the physicalparameters of the drive. For example, a disk drive with 1024 cylinders,256 heads and 63 sectors per track has (1024)×(256)×(63)=16,515,072sectors. Each sector can be physically addressed based on itscorresponding cylinder, head and sector number, e.g. cylinder 437, head199, sector 12. A test pattern is written to, and read from, each disksector in physical mode to determine which sectors of the disk are goodand are available for storage, and which sectors are bad and should notbe used.

The sectors of the disk are assigned a logical block address (LBA) thattranslates the physical sectors of the drive into a linear, sequentiallynumbered set of blocks that includes the good sectors and excludes thebad sectors. These LBA addresses are used in communicating with a hostdevice in host interface protocols such as small computer systeminterface (SCSI) or serial advanced technology attachment (SATA), inorder to write to or read data from the drive. In formatting the driveat the factory, the drive is completely rewritten in logical mode, usingthe assigned LBAs, for access by the user once the drive is installedand coupled to a host device. When a user of a host device reads datafrom the drive, he reads the data in logical mode. If a sector that waswritten in physical address mode were attempted to be read by a user inlogical mode, the user would receive errors related to the blockaddress.

A sizable market has developed for these devices and the price per unitof storage has steadily dropped. Modern host devices are provided withgreater storage capacity at reduced cost, compared with devices thatwhere manufactured a few years earlier. The need exists for provide harddrives that can be manufactured efficiently on a mass scale with reducedcost.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 presents a pictorial representation of a disk drive unit 100 inaccordance with an embodiment of the present invention.

FIG. 2 presents a block diagram representation of a disk controller 130in accordance with an embodiment of the present invention.

FIG. 3 presents a block diagram representation of a disk formatter 125in accordance with an embodiment of the present invention.

FIG. 4 presents a graphical representation of a disk block address 175in accordance with an embodiment of the present invention.

FIG. 5 presents a pictorial representation of a handheld audio unit 51in accordance with an embodiment of the present invention.

FIG. 6 presents a pictorial representation of a computer 52 inaccordance with an embodiment of the present invention.

FIG. 7 presents a pictorial representation of a wireless communicationdevice 53 in accordance with an embodiment of the present invention.

FIG. 8 presents a pictorial representation of a personal digitalassistant 54 in accordance with an embodiment of the present invention.

FIG. 9 presents a pictorial representation of a laptop computer 55 inaccordance with an embodiment of the present invention.

FIG. 10 presents a flowchart representation of a method in accordancewith an embodiment of the present invention.

FIG. 11 presents a flowchart representation of a method in accordancewith an embodiment of the present invention.

FIG. 12 presents a flowchart representation of a method in accordancewith an embodiment of the present invention.

SUMMARY OF THE INVENTION

The present invention sets forth a disk formatter and methods for usetherewith substantially as shown in and/or described in connection withat least one of the figures, as set forth more completely in the claimsthat follow.

DETAILED DESCRIPTION OF THE INVENTION INCLUDING THE PRESENTLY PREFERREDEMBODIMENTS

The present invention provides several advantages over the prior art. Inan embodiment of the present invention, a disk formatter and relatedmethods are presented that allows disk sectors to be written in physicalmode in a manner consistent with logical block addressing. In anembodiment, data that is written in physical mode can be read in logicalmode without receiving errors relating to the block address.

In an embodiment of the present invention, the factory formatting of thedisk drive need not rewrite the disk in logical mode. This eliminates astep in the manufacturing process, reduces the production cycle time,and lowers the overall cost of production.

FIG. 1 presents a pictorial representation of a disk drive unit 100 inaccordance with an embodiment of the present invention. In particular,disk drive unit 100 includes a disk 102 that is rotated by a servo motor(not specifically shown) at a velocity such as 3600 revolutions perminute (RPM), 4200 RPM, 4800 RPM, 5,400 RPM, 7,200 RPM, 10,000 RPM,15,000 RPM, however, other velocities including greater or lesservelocities may likewise be used, depending on the particular applicationand implementation in a host device. In an embodiment of the presentinvention, disk 102 can be a magnetic disk that stores information asmagnetic field changes on some type of magnetic medium. The medium canbe a rigid or nonrigid, removable or nonremovable, that consists of oris coated with magnetic material.

Disk drive unit 100 further includes one or more read/write heads 104that are coupled to arm 106 that is moved by actuator 108 over thesurface of the disk 102 either by translation, rotation or both. A diskcontroller 130 is included for controlling the read and write operationsto and from the drive, for controlling the speed of the servo motor andthe motion of actuator 108, and for providing an interface to and fromthe host device. Disk controller 130, provides one or more functions orfeatures of the present invention, as described in further detail inconjunction with the figures that follow.

FIG. 2 presents a block diagram representation of a disk controller 130in accordance with an embodiment of the present invention. Inparticular, disk controller 130 includes a read/write channel 140 forreading and writing data to and from disk 102 through read/write heads104. Disk formatter 125 is included for controlling the formatting ofdata and provides clock signals and other timing signals that controlthe flow of the data written to, and data read from disk 102 servoformatter 120 provides clock signals and other timing signals based onservo control data read from disk 102, device controllers 105 controlthe operation of drive devices 109 such as actuator 108 and the servomotor, etc. Host interface 150 receives read and write commands fromhost device 50 and transmits data read from disk 102 along with othercontrol information in accordance with a host interface protocol. In anembodiment of the present invention the host interface protocol caninclude, SCSI, SATA, enhanced integrated drive electronics (EIDE), orany number of other host interface protocols, either open or proprietarythat can be used for this purpose.

Disk controller 130 further includes a processing module 132 and memorymodule 134. Processing module 132 can be implemented using one or moremicroprocessors, micro-controllers, digital signal processors,microcomputers, central processing units, field programmable gatearrays, programmable logic devices, state machines, logic circuits,analog circuits, digital circuits, and/or any devices that manipulatessignal (analog and/or digital) based on operational instructions thatare stored in memory module 134. When processing module 132 isimplemented with two or more devices, each device can perform the samesteps, processes or functions in order to provide fault tolerance orredundancy. Alternatively, the function, steps and processes performedby processing module 132 can be split between different devices toprovide greater computational speed and/or efficiency.

Memory module 134 may be a single memory device or a plurality of memorydevices. Such a memory device may be a read-only memory, random accessmemory, volatile memory, non-volatile memory, static random accessmemory (SRAM), dynamic random access memory (DRAM), flash memory, cachememory, and/or any device that stores digital information. Note thatwhen the processing module 132 implements one or more of its functionsvia a state machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory module 134 storing the corresponding operationalinstructions may be embedded within, or external to, the circuitrycomprising the state machine, analog circuitry, digital circuitry,and/or logic circuitry. Further note that, the memory module 134 stores,and the processing module 132 executes, operational instructions thatcan correspond to one or more of the steps or a process, method and/orfunction illustrated herein.

Disk controller 130 includes a plurality of modules, in particular,device controllers 105, processing timing generator 110, processingmodule 132, memory module 134, read/write channel 140, disk formatter125, servo formatter 120 and host interface 150 that are interconnectedvia buses 136 and 137. Each of these modules can be implemented inhardware, firmware, software or a combination thereof, in accordancewith the broad scope of the present invention. While a particular busarchitecture is shown in FIG. 2 with buses 136 and 137, alternative busarchitectures that include either a single bus configuration oradditional data buses, further connectivity, such as direct connectivitybetween the various modules, are likewise possible to implement thefeatures and functions included in the various embodiments of thepresent invention.

In an embodiment of the present invention, one or more modules of diskcontroller 130 are implemented as part of a system on a chip integratedcircuit. In an embodiment of the present invention, this system on achip integrated circuit includes a digital portion that can includeadditional modules such as protocol converters, linear block codeencoding and decoding modules, etc., and an analog portion that includesadditional modules, such as a power supply, disk drive motor amplifier,disk speed monitor, read amplifiers, etc. In a further embodiment of thepresent invention, the various functions and features of disk controller130 are implemented in a plurality of integrated circuit devices thatcommunicate and combine to perform the functionality of disk controller130.

When the drive unit 100 is manufactured, it is formatted for the firsttime. Disk formatter 125 controls the formatting operation of the drivein order to implement one or more of the features and functions of thepresent invention, as will be described in further detail in conjunctionwith the figures that follow.

FIG. 3 presents a block diagram representation of a disk formatter 125in accordance with an embodiment of the present invention. Inparticular, disk formatter includes an address module 110 for creatingdisk block address data corresponding to a disk sector of a disk drive,such as disk drive unit 100. Sector write module 114 is operably coupledto the address module for initiating a physical mode write operation tothe disk sector that incorporates the corresponding disk block addressdata.

In accordance with an embodiment of the present invention, the diskdrive unit 100 is initially formatted as follows. Each sector of thedisk 102 is written with a bit pattern, such as a 2T pattern, that canbe used to test the read/write ability of the various sectors. The datafrom each sector of the disk is read and compared with the pattern. Whenunacceptable deviations are detected, this information is used toeliminate a first group of bad sectors. A second write operation isinitiated to the remaining sectors (the sectors that were not eliminatedduring the first test) by performing a physical mode write operation toeach sector. Each sector is written with data that incorporates diskblock address data that contains an identifier that the sector waswritten in physical mode. The formatting of the disk drive unit 100continues by reading the sector data and determining a bit error rate(BER) for each sector. If the BER for a particular sector is above athreshold, such as a threshold that is below the rate that can bereliably corrected with the error correcting code employed (e.g. a ReedSolomon code), the sector is also declared bad. A primary defect tableis populated with information that is sufficient to identify each of thebad sectors and the formatting of disk drive unit 100 is competed. Inparticular, the good sectors of disk drive unit 100 are not rewritten inlogical mode during this initial formatting. As mentioned above, thiseliminates a step in the manufacturing process, reduces the productioncycle time, and lowers the overall cost of production.

In an embodiment of the present invention, certain good sectors of diskdrive unit 100 are set aside during the formatting process for use as autility zone for storing drive code. This drive code is written inphysical mode with a corresponding utility block address (UBA), that isincorporated into the DBA of each utility zone sector. Access to thisdrive code by disk controller 130 can be accomplished in physical mode.In this embodiment of the present invention, the sector of the utilityzone are treated as bad sectors for the purposes of translating thesectors to logical mode addressing, because these sectors are notavailable for storage by the user.

In an embodiment of the present invention, the sector write module 114initiates a physical mode write operation that incorporates the diskblock address data by storing the corresponding disk block address datain the disk sector. In this fashion, n bits of the disk block addressdata (encoded as m encoded bits or left as n unencoded bits) are storedas part of the overhead data of the corresponding sector. In a furtherembodiment of the present invention, the n bits of the disk blockaddress are used as seeds to the error correcting code algorithm used toencode and decode the sector data. In this embodiment, the disk blockaddress data can be incorporated in the sector data, without taking upadditional bits of sector overhead.

In accordance with an embodiment of the present invention, the diskdrive unit is subsequently installed in conjunction with a host device50. A logical read/write operation to a sector that was written inphysical mode does not generate an address error. When a write operationis directed to virgin sector, one that has not been previously writtenin logical mode, the physical mode identifier of the disk block addressdata identifies that the sector was written in physical mode. The sectorcan then be written in logical mode and accessed normally from thatpoint forward.

FIG. 4 presents a graphical representation of a disk block address 175in accordance with an embodiment of the present invention. Inparticular, one possible data structure for disk block address 175 ispresented. In this embodiment, disk block address includes 48 bits ofdata (four 12-bit symbols). The most significant bit is reserved for aphysical mode flag field for storing physical mode flag 200 that has afirst value if the disk sector is written in physical mode and anothervalue if the disk sector is written in another mode, such as logicalmode. The disk block address 175 also includes a logical block addressdata field 202 of the disk sector. The disk block address 175 furtherincludes a utility block address data field of the sector. While thisdescription presents one possible data structure for disk block address175, other data structures using greater or fewer numbers of bits,alternative partitioning including greater or lesser data fields arelikewise possible within the broad scope of the present invention. In anembodiment of the present invention that does not employ a utility zone,the second data field 203 can be omitted.

During a formatting operation when sectors of disk 102 are written inphysical mode, sector write module 114 initiates the physical mode writeoperation to the disk sector with a DBA 175 wherein the physical modeflag 200 is set to a physical mode value, the logical block address datafield 202 stores a default value, and the utility block address datafield 204 stores a default value, because it has not yet been determinedif the if the sector is destined to become a “bad sector” that has notranslated logical block address, a “good sector” with a correspondingthe logical block address or part of the utility zone.

If the sector is subsequently written as part of an operation of writingdrive code or other data to a utility zone, a utility block address thatcorresponds to that sector is determined and stored in second data field203. The utility block address for the sector can be any data field thatcan be used to address the particular sectors that are a part of theutility zone. In an embodiment of the present invention, the utilityblock address includes the physical mode address of the particularsector. While the description above discussions initially storing adefault value in the utility block address data field, in an alternativeembodiment of the present invention the physical mode address may bestored in the utility mode address data field during formatting.

If the sector is subsequently written as part of a normal writeoperation on behalf of a host device 50 in logical mode, a logical blockaddress that corresponds to that sector is determined and stored inlogical block address data field 202. The logical block address for thesector can be determined based on the file system, such as fileallocation table (FAT) or new technology file system (NTFS) that isemployed, along with the particular host interface protocol, such asSCSI, SATA, etc, as will be understood by one skilled in the art whenpresented the present disclosure.

While the foregoing description includes a physical mode flag 200 withone or more bits that stores a value that indicates whether the sectorwas written in physical mode or some other mode such a logical mode,other indicators representing some or all bits of disk block address 175such as a pattern of all 1's, all 0's, an alternating patterns of 1'sand 0's, or some other word or pattern could likewise be used inconjunction with the broad scope of the present invention.

While the foregoing description discusses the formatting of disk driveunit 100 during initial formatting as part of the factory setup andinitialization of the drive, subsequent formatting operations of diskdrive unit 100 can also be carried out in accordance with the presentinvention.

FIG. 5 presents a pictorial representation of a handheld audio unit 51in accordance with an embodiment of the present invention. Inparticular, disk drive unit 100 can include a small form factor magnetichard disk whose disk 102 has a diameter 1.8″ or smaller that isincorporated into or otherwise used by handheld audio unit 51 to providegeneral storage or storage of audio content such as motion pictureexpert group (MPEG) audio layer 3 (MP3) files or Windows MediaArchitecture (WMA) files, video content such as MPEG4 files for playbackto a user, and/or any other type of information that may be stored in adigital format.

FIG. 6 presents a pictorial representation of a computer 52 inaccordance with an embodiment of the present invention. In particular,disk drive unit 100 can include a small form factor magnetic hard diskwhose disk 102 has a diameter 1.8″ or smaller, a 2.5″ or 3.5″ drive orlarger drive for applications such as enterprise storage applications.Disk drive 100 is incorporated into or otherwise used by computer 52 toprovide general purpose storage for any type of information in digitalformat. Computer 52 can be a desktop computer, or an enterprise storagedevices such a server, of a host computer that is attached to a storagearray such as a redundant array of independent disks (RAID) array,storage router, edge router, storage switch and/or storage director.

FIG. 7 presents a pictorial representation of a wireless communicationdevice 53 in accordance with an embodiment of the present invention. Inparticular, disk drive unit 100 can include a small form factor magnetichard disk whose disk 102 has a diameter 1.8″ or smaller that isincorporated into or otherwise used by wireless communication device 53to provide general storage or storage of audio content such as motionpicture expert group (MPEG) audio layer 3 (MP3) files or Windows MediaArchitecture (WMA) files, video content such as MPEG4 files, JPEG (jointphotographic expert group) files, bitmap files and files stored in othergraphics formats that may be captured by an integrated camera ordownloaded to the wireless communication device 53, emails, webpageinformation and other information downloaded from the Internet, addressbook information, and/or any other type of information that may bestored in a digital format.

In an embodiment of the present invention, wireless communication device53 is capable of communicating via a wireless telephone network such asa cellular, personal communications service (PCS), general packet radioservice (GPRS), global system for mobile communications (GSM), andintegrated digital enhanced network (iDEN) or other wirelesscommunications network capable of sending and receiving telephone calls.Further, wireless communication device 53 is capable of communicatingvia the Internet to access email, download content, access websites, andprovide steaming audio and/or video programming. In this fashion,wireless communication device 53 can place and receive telephone calls,text messages such as emails, short message service (SMS) messages,pages and other data messages that can include attachments such asdocuments, audio files, video files, images and other graphics.

FIG. 8 presents a pictorial representation of a personal digitalassistant 54 in accordance with an embodiment of the present invention.In particular, disk drive unit 100 can include a small form factormagnetic hard disk whose disk 102 has a diameter 1.8″ or smaller that isincorporated into or otherwise used by personal digital assistant 54 toprovide general storage or storage of audio content such as motionpicture expert group (MPEG) audio layer 3 (MP3) files or Windows MediaArchitecture (WMA) files, video content such as MPEG4 files, JPEG (jointphotographic expert group) files, bitmap files and files stored in othergraphics formats, emails, webpage information and other informationdownloaded from the Internet, address book information, and/or any othertype of information that may be stored in a digital format.

FIG. 9 presents a pictorial representation of a laptop computer 55 inaccordance with an embodiment of the present invention. In particular,disk drive unit 100 can include a small form factor magnetic hard diskwhose disk 102 has a diameter 1.8″ or smaller, or a 2.5″ drive. Diskdrive 100 is incorporated into or otherwise used by laptop computer 52to provide general purpose storage for any type of information indigital format.

FIG. 10 presents a flowchart representation of a method in accordancewith an embodiment of the present invention. In particular, a method ispresented that can be used in conjunction with one or more of thefeatures or functions described in association with FIGS. 1-9. In step400, disk block address data are created corresponding to a disk sectorof a disk drive. In step 402, a physical mode write operation isinitiated to the disk sector that incorporates the corresponding diskblock address data.

In an embodiment of the present invention the corresponding disk blockaddress data includes a value that indicates that the disk sector waswritten in physical mode. In an embodiment, the value that indicatesthat the disk sector was written in physical mode includes a physicalmode flag field that has a first value if the disk sector is written inphysical mode and at least one other value if the disk sector is writtenin another mode. However, other values or indicators may be used aspreviously described.

In an embodiment of the present invention, step 400 includes creating alogical block address data field, and creating a utility block addressdata field. In an embodiment, step 402 includes storing either a logicalblock address of the disk sector or a default value in the logical blockaddress data field, and storing either a utility block address of thedisk sector or a default value in the utility block address data field.In an embodiment of the present invention, the step of initiating aphysical mode write operation includes storing the corresponding diskblock address data in the disk sector, provided however that indirectstorage of the disk block address may also be employed as previouslydescribed.

FIG. 11 presents a flowchart representation of a method in accordancewith an embodiment of the present invention. In particular, a method ispresented that can be used in conjunction with one or more of thefeatures or functions described in association with FIGS. 1-10. In step500, disk block address data is read from a disk block address field ofa disk sector of a disk drive. In step 502, the method determines if thedisk sector was written in physical mode, based on the disk blockaddress data.

In an embodiment of the present invention, step 502 includes determiningif the disk block address data includes a value that indicates that thedisk sector was written in physical mode. In an embodiment, step 502includes determining if the disk block address data includes a physicalmode flag field that has a first value if the disk sector is written inphysical mode and at least one other value if the disk sector is writtenin another mode.

FIG. 12 presents a flowchart representation of a method in accordancewith an embodiment of the present invention. In particular, a method ispresented that can be used in conjunction with one or more of thefeatures or functions described in association with FIGS. 1-11. In step500, disk block address data is read from a disk block address field ofa disk sector of a disk drive. In step 510, the method determines if thedisk sector was written in physical mode, based on the disk blockaddress data, if not the method continues. In an embodiment of thepresent invention, step 510 includes determining if the disk blockaddress data includes a value that indicates that the disk sector waswritten in physical mode. In an embodiment, step 510 includesdetermining if the disk block address data includes a physical mode flagfield that has a first value if the disk sector is written in physicalmode and at least one other value if the disk sector is written inanother mode.

If the disk sector was written in physical mode, the method proceeds tostep 512 to determine if the sector is a LBA sector that is missing theLBA. For instance, a disk controller is attempting a read/writeoperation in logical mode to a sector that was written in physical mode.In this example, the logical block address data field may contain adefault value. If so, the method proceeds to step 516 where the methoddetermines a logical block address data for the disk sector. The methodcontinues with step 520 where the logical block address data is storedin the disk block address field. In addition, in the embodiment whereinthe disk block address data includes a physical mode flag field that hasa first value if the disk sector is written in physical mode and atleast one other value if the disk sector is written in another mode—thephysical mode flag is reset so that subsequent read/write operations tothe sector will proceed normally in logical mode.

If step 512 determined that the sector is not an LBA sector, the methodproceeds to step 514 to determine if the sector is a utility zone sectorthat is missing the UBA. For instance, a disk controller is attempting aread/write operation in physical mode to a sector that is part of theutility zone that may contain a default value for in the utility blockaddress data field if it is being accessed for the first time. If so,the method proceeds to step 518 by determining a utility block addressdata for the disk sector. The method proceeds to step 522 by storing theutility block address data in the disk block address field. If, in step514, the method determines that this is a utility zone sector that isnot missing its UBA, the method continues.

While the present invention has been described in terms of a magneticdisk, other nonmagnetic storage devices including optical disk drivesincluding compact disks (CD) drives such as CD-R and CD-RW, digitalvideo disk (DVD) drives such as DVD-R, DVD+R, DVD-RW, DVD+RW, etc canlikewise be implemented in accordance with the functions and features ofthe presented invention described herein.

As one of ordinary skill in the art will appreciate, the term“substantially” or “approximately”, as may be used herein, provides anindustry-accepted tolerance to its corresponding term and/or relativitybetween items. Such an industry-accepted tolerance ranges from less thanone percent to twenty percent and corresponds to, but is not limited to,component values, integrated circuit process variations, temperaturevariations, rise and fall times, and/or thermal noise. Such relativitybetween items ranges from a difference of a few percent to magnitudedifferences. As one of ordinary skill in the art will furtherappreciate, the term “operably coupled”, as may be used herein, includesdirect coupling and indirect coupling via another component, element,circuit, or module where, for indirect coupling, the interveningcomponent, element, circuit, or module does not modify the informationof a signal but may adjust its current level, voltage level, and/orpower level. As one of ordinary skill in the art will also appreciate,inferred coupling (i.e., where one element is coupled to another elementby inference) includes direct and indirect coupling between two elementsin the same manner as “operably coupled”. As one of ordinary skill inthe art will further appreciate, the term “compares favorably”, as maybe used herein, indicates that a comparison between two or moreelements, items, signals, etc., provides a desired relationship. Forexample, when the desired relationship is that signal 1 has a greatermagnitude than signal 2, a favorable comparison may be achieved when themagnitude of signal 1 is greater than that of signal 2 or when themagnitude of signal 2 is less than that of signal 1.

The various circuit components can be implemented using 0.35 micron orsmaller CMOS technology. Provided however that other circuittechnologies, both integrated or non-integrated, may be used within thebroad scope of the present invention. Likewise, various embodimentsdescribed herein can also be implemented as software programs running ona computer processor. It should also be noted that the softwareimplementations of the present invention can be stored on a tangiblestorage medium such as a magnetic or optical disk, read-only memory orrandom access memory and also be produced as an article of manufacture.

Thus, there has been described herein an apparatus and method, as wellas several embodiments including a preferred embodiment, forimplementing a memory and a processing system. Various embodiments ofthe present invention herein-described have features that distinguishthe present invention from the prior art.

It will be apparent to those skilled in the art that the disclosedinvention may be modified in numerous ways and may assume manyembodiments other than the preferred forms specifically set out anddescribed above. Accordingly, it is intended by the appended claims tocover all modifications of the invention which fall within the truespirit and scope of the invention.

1. A method comprising: creating disk block address data correspondingto a disk sector of a disk drive wherein the disk block address dataincludes a value that indicates that the disk sector was written inphysical mode; and initiating a physical mode write operation to thedisk sector that incorporates the corresponding disk block address data.2. The method of claim 1 wherein the step of creating disk block addressdata corresponding disk block address data includes creating a logicalblock address data field.
 3. The method of claim 2 wherein the step ofcreating disk block address data corresponding disk block address dataincludes storing in the logical block address data field one of: alogical block address, and a default value.
 4. The method of claim 1wherein the step of creating disk block address data includes creating autility block address data field.
 5. The method of claim 4 wherein thestep of creating disk block address data corresponding disk blockaddress data includes storing in the utility block address data fieldone of: a utility block address, and a default value.
 6. The method ofclaim 1 wherein the value that indicates that the disk sector waswritten in physical mode includes a physical mode flag field that has afirst value if the disk sector is written in physical mode and at leastone other value if the disk sector is written in another mode.
 7. Themethod of claim 1 wherein the step of initiating a physical mode writeoperation includes storing the corresponding disk block address data inthe disk sector.
 8. A method comprising: reading disk block address datafrom a disk block address field of a disk sector of a disk drive; anddetermining if the disk sector was written in physical mode, based onthe disk block address data.
 9. The method of claim 8 furthercomprising: determining logical block address data for the disk sector;and storing the logical block address data in the disk block addressfield.
 10. The method of claim 8 further comprising: determining utilityblock address data for the disk sector; and storing the utility blockaddress data in the disk block address field.
 11. The method of claim 8wherein the step of determining if the disk sector was written inphysical mode includes determining if the disk block address dataincludes a value that indicates that the disk sector was written inphysical mode.
 12. The method of claim 8 wherein determining if the disksector was written in physical mode includes determining if the diskblock address data includes a physical mode flag field that has a firstvalue if the disk sector is written in physical mode and at least oneother value if the disk sector is written in another mode.